1) advanced 1337 slang phrase for "pwnd" or "prawnd"
2) the act of entering a state of being covered in human excrement
3) internet phrase to express utter humiliation during an online game

other variations include: having become shat upon, became shat upon, become shit on, will have been shat upon (the grammatically incorrect use of "shatting" is sometimes used in place of "shat" to express a continuing action)